1. Field of the Invention
The present invention relates to a pattern misalignment measurement method, a program, and a semiconductor device manufacturing method.
2. Related Background Art
To take a semiconductor device as an example, an alignment technique in a photolithographic process is important in the manufacture of the semiconductor device, and a misalignment inspection process for inspecting an alignment result is an essential technique together with a critical dimension (CD) measurement process to manufacture a micro unit with a high yield. A method using an optical inspection apparatus has heretofore been used for a misalignment inspection. In addition to this method, another method has been recently proposed which uses an electron beam (EB) with a good resolution to achieve the misalignment inspection with higher accuracy.
A common point between the inspection using the electron beam and the method using the optical inspection apparatus is that an SEM image is acquired by use of an inspection apparatus which uses a scanning electron microscope such as a critical dimension scanning electron microscope (CDSEM), and the obtained image is analyzed to obtain a desired numerical value.
However, in both the optical inspection apparatus and the EB inspection apparatus, the above-mentioned conventional technique requires the use of a special pattern structure (inspection mark) for misalignment measurement. Specifically, this has led to the following problems:    1. Costs are required to form the inspection mark.    2. The misalignment measurement in the center of a device is impossible because the inspection mark can only be disposed in peripheral parts of the device.    3. The misalignment measurements have to be carried out independently in an X direction and a Y direction, and much time is therefore taken for the measurements.